variable message sign is used to support and strengthen LED traffic signal system and it won’t be an exaggeration to say that CMS is part of the traffic management system. Just like traffic lights manage flow of traffic, DMS boards manage the movement of vehicles. Drivers read the messages display on VMS boards and plan their routes. A question here arises that is could these boards be used for marketing and branding. And its answer is no.
http://www.onnyx.in/variable-message-sign-vms.html

Careless drivers should be careful as the traffic control system has turned into an adaptive traffic control system that is much better than the outgoing technology. Now the lights are managed from a central command center that keeps control of every traffic light. This system is intelligent as it can plan a quick strategy for managing urban traffic.
http://www.onnyx.in/microprocessor-based-road-traffic-signal-controller.html